Selectively collapsible stay arm



Feb; 13, 1968- FAZEKAS ETAI- 3,368,423

SELECTIVELY COLLAPSIBLE STAY ARM I Filed Nov. 17, 1965 VIlV FIG. 5;

INVENTORS CHARLES FAZEKAS. FLOYD LAMBERT ATTORNEYS.

United States Patent Filed Nov. 17, 1965, Ser. No. 508,274 Claims. (Cl. 74-527) ABSTRACT OF THE DISCLOSURE A selectively collapsible stay arm formed by a pivotally interconnected body member and leg member with a locking sleeve telescopically arranged on said body member for longitudinal movement from a position overlying the body member to a position overlying both body member and leg member to secure said members in a fixed load supporting relationship.

Background of the invention A variety of situations exist in which a collapsible stay armor strut is employed to support a shelf member, or the like, in a fashion permitting folding of the shelf member away out of operative position when desired. The supporting strut must be subject to collapse when it is desired to fold the supported surface out of operative position. Collapse of the strut should be attainable with minimum manipulative effort. However, the str-ut or arm when extended to supporting position must be sufficiently rigid and secure to provide desired support when the table surface or the like is arranged in operative position. It is desired that such stay arms or supporting struts automatically assume a distended operative supporting position when the table surface with which they are associated is lifted or otherwise arranged in operative position. Conversely it is desired that collapse of the strut be subject to attainment in a simple manner without requiring the exercise of particular skills. Previously evolved supporting struts of this type have presented problems in that the locking mechanism employed for main taining the strut components in operative orientation to support a table surface are relatively expensive particularly when the loads supported are heavy. Where expense is avoided, the locking mechanism is often subject to failure. Other problems arise in that release of the locking mechanism to permit collapse of the table often results in a pinching of the fingers of the user.

Summary It is with the above problems and desiderata in mind that the present improved stay arm or supporting strut has been evolved, a supporting strut of a simple nature permitting the use of relatively heavy structural components, so as to permit use of the strut for supporting relatively heavy loads, while providing a positive locking mechanism which prevents inadvertent collapse of the supporting strut, or conversely permits collapse in a simple fashion without endangering the hands of the user.

It is accordingly among the primary objects of this invention to provide an improved collapsible stay arm or strut particularly adapted for heavy-duty use.

Another object of the invention is to provide a collapsible stay arm or strut with a manually manipulable 2 locking mechanism permitting manual manipulation without endangering the hands of the user.

A further object of the invention is to provide a collapsible stay arm or strut having a locking mechanism for maintaining the strut components in an operative supporting position with the locking mechanism automatically actuated as the stay arm components are oriented for use.

A further object of the invention is to provide a stay arm with a locking mechanism which though subject to relatively easy manual release is not subject to accidental or shock displacement.

These and other objects of the invention which will become hereafter apparent are achieved by forming a stay arm or strut assembly of two pivotally interconnected members. In the illustrated preferred embodiment of the invention, as will be hereafter more fully described, these members are of substantially equal length, and one of said members will be referred to as a body, while the other will be referred to as a leg. .Slideably mounted on one of said members, preferably the body member, is a locking mechanism which is biased preferably by spring biasing to move to a limiting position engaging a part of the leg. The part of the leg which is engaged by the locking mechanism is in the form of a detent, and the locking mechanism is provided With a latch slot in which said detent is accommodated. A cam is formed at the entry end of the latch slot over which the detent will ride as pivotal movement takes place between the body and leg members. Thus as the body and leg members are pivoted with respect to each other so that the body and leg will assume an operative supporting orientation, the detent will be guided into the slideway for engagement by the locking mechanism in a positive fashion. Release of the detent from the locking slideway requires manual retraction of the locking mechanism against its spring biasing, thus freeing the detent, and simultaneously permitting pivoting of the body member with respect to the leg member.

A feature of the invention resides in the arrangement of the spring biasing element in a housing which forms a thumb engaging abutment on the locking mechanism which is dimensioned for ready manual gripping, so that release of the locking mechanism requires that the hands of an operator be positioned at a point preventing pinching of the fingers or any part of the hand.

Another feature of the invention resides in the provision of simple means for securing the locking mechanism in any desired position with respect to the leg or body members, so that the locking mechanism may either be deactivated, or may be maintained in a position preventing displacement of the locking mechanism, and collapse of the strut.

Brief description of the drawing The specific details of a preferred embodiment of the invention, and their mode of functioning will be parthe left-hand side of a downwardly pivoted table or shelf;

FIG. 2 is a side view looking at the structure shown in FIG. 1 from the right-hand side thereof;

FIG. 3 is a fragmentary view showing the pivot portion of the strut, looking at the structure shown in FIG. 1 from the obverse side shown in FIG. 1;

FIG. 4 is a cross-sectional view taken on line 44 of FIG. 3 illustrating the relationship between the locking sleeve, the body, and the leg; and

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 1 showing the stop member.

Description the preferred embodiment Referring now more particularly to the drawings, like numerals in the various figures will be employed to designate like parts.

As best seen in FIGS. 1 and 2, the strut assembly 10 is seen to comprise three major cooperating parts in which the body member is generally designated by the numeral 11, the leg member is generally designated by the numeral 12, and the locking mechanism is generally designated by the numeral 15.

Body member 11 is formed of an elongate strip of relatively rigid material such as steel or the like, and is preferably of rectangular cross-section, as best seen in FIG. 4. A free end 16 of body member 11 is rounded and provided with a pivot pin aperture 17. The other end of body member 11 is pivotally connected to leg 12 and is referred to as pivot end 18. Pivot end 18 is rounded and is formed wit-h a pivot pin opening 19. A shoulder 22 is formed on pivot end 18 which extends perpendicular to the plane of the body member 11, and a transition area 23 of reduced cross-section is provided for a purpose to become hereinafter apparent.

Pivotally secured to the body member 11 is the leg member 12, which as best seen in FIGS. 1 and 2 is similarly formed of an elongate rigid material, preferably of bar stock rectangular in cross-section. Leg 12 is formed with a pivot section 25 having a pivot hole 26 adapted for alignment with pivot hole 19 of body member 11. Extending from this pivot portion 25, as best seen in FIG. 3 is a detent 28, preferably dimensioned of a cross-section less than that of the cross-section of the leg 12. Upstanding from the plane of pivot portion 25, on the side thereof contacting body member 11, is a stop 31, which as seen in FIG. extends from the surface of pivot portion 25 a distance substantially equal to the thickness of body member 11, and is of a width substantially equal to the width of shoulder 22, as best seen in FIG. 1, Beyond the pivot portion 25, leg member 12 is formed with an offset portion 35, as best seen in FIG. 2, which is preferably offset from the plane of pivot portion 25 an amount equal to the thickness of leg member 12. The free end 38 of leg'12 is rounded and is provided with a pivot pin opening 39, as best seen in FIGS. 1 and 2.

Pivot pin 41 is extended between body member 11 and pivot portion 25 of leg member 12 by inserting the pivot pin through pivot apertures 19 and 26 respectively. One end of pivot pin 41 is provided with a head 42 and the other end is upset as at 43 to effect locking of the pin 41 in desired operative position.

Locking mechanism 15 comprises a sleeve 45 formed of sheet material such as steel or the like. Sleeve 45 is preferably dimensioned of a length such as to permit the hand of an average user to extend comfortably about the sleeve. A length between three and five inches is found particularly suitable. Sleeve 45 is formed with a detent slot portion 46, as best seen in FIGS. 1 and 3, which is dimensioned to slideably accommodate detent 28. The sleeve 45 is formed with a slideway 50, preferably on the side thereof opposite slot 46. A key 52 of an L-shaped configuration, as best seen in FIG. 2, is secured to body member 11 within slot 50, the dimensioning of key 52 being such as to permit free movement of the slideway over the key. The key 52 in the illustrated embodiment is secured to body 11 by means of machine screws 54. A spring housing 60 formed of sheet steel is welded to the sleeve 45 over a part of slideway 50. The length of slideway 50 is such as to accommodate therein compression spring 62 and key 52, One end of housing 60 is closed to provide a thumb rest 64, while the other end of housing 60 is open, with upstanding foot 65 of key 52 acting as a closure to contain spring 62 within the housing 60. A cam surface 68 is formed on sleeve 45 adjacent the entry to slot 46, so as to cooperate with detent 28, as best seen in FIG. 3, and guide same into slot 46 while displacing the sleeve 45 against the biasing action of spring 62.

A machine screw 75 is arranged in threaded engagement with body member 11 and the head end of the machine screw 75 extends through slot 76 formed in sleeve 45, as best seen in FIGS. 1 and 2.

Operation The aforedescribed stay arm or supporting strut assembly 10 may be employed in any of a large variety of situations where it is desired to provide a collapsible supporting member. Thus when it is necessary to provide support for a foldaway shelf or table, one or more strut assemblies of the type here disclosed may be employed. Additionally the strut assembly or stay arm may be employed in connection with a vertically hinged member such as a door to maintain the door in an open position.

In use, it is preferred to pivotally secure one end of the strut assembly between a wall of the member to which the shelf is hinged, and pivotally secure the other end of the strut to the shelf. It will be understood that the strut is arranged at a distance from the hinge point of the shelf, table, or door which is being supported so that the pivot connections between the ends of the strut and the shelf and cabinet respectively form an isosceles triangle, or a slide pivot is formed at one of the pivot connections in the event that this isosceles arrangement cannot be obtained. The strut is arranged with the housing 60 extending outwardly of the strut. Thus the illustrated stay arm or strut is of a left-hand type in which it is intended that the left hand of the user be employed to grip the sleeve 45, with the thumb of the user bearing against thumb rest 64.

When the shelf in connection with which the stay arm is employed is brought to an operative position, leg member 12 will pivot with respect to body member 11 about pivot pin 41 until detent 28 contacts cam surface 68 of sleeve 45, as best seen in FIG. 3. Continued movement of the detent against cam 68 displaces sleeve 45 against the biasing action of spring 62 until the detent is aligned with latch slot 46, at which time the biasing action of the spring 62 causes the sleeve 45 to assume the position illustrated in FIG. 1 securely locking leg 12 in an extended operative position with respect to body member 11. In order to prevent detent 28 from overriding the entry to detent slot 46, stop 31 engages shoulder 22 to limit the relative pivoting between leg 12 and body 11.

Thereafter when it is desired to close the shelf, which necessitates collapse of the stay arm 10, the sleeve 45 is gripped with the thumb resting against thumb rest 64. By pulling on the thumb rest 64 sleeve 45 is retracted to release detent 28 and the application of manual pressure transverse to the axis of body member 11 results in a pivoting of the body member with respect to the leg member to cause collapse of the strut, In collapsed position the stop 31 folds into the space provided by the reduced cross-section of transition area 23.

The above disclosure has been given by way of illustration and elucidation, and not by way of limitation, and it is desired to protect all embodiments of the herein disclosed inventive concept within the scope of the appended claims.

What is claimed is:

1. A stay arm comprising a leg member pivotally connected to a body member; an end projecting portion of said leg member providing a detent portion; locking means including a sleeve telescopically arranged on said body 5 member for longitudinal movement; a cam on said sleeve cooperating with said detent portion on said leg member; and a detent slot portion on said sleeve engaging said leg member projecting detent portion.

2. A stay arm as in claim 1 having: a spring mounted between said body member and said sleeve for yieldably urging said sleeve'in a direction towards said pivot connection between said leg and body members.

3. A stay arm as in claim 2 in which: a housing is formed on said sleeve Within which said spring is mounted; and a thumb rest on said housing; said housing having a slideway; and a key in said slideway guiding said sleeve.

4. A stay arm as in claim 1; further comprising manually operable means for selectively fixing said sleeve with respect to said body, said manually operable means com- References Cited UNITED STATES PATENTS 254,324 2/1882 Iglehart 292263 X 1,136,444 4/1915 Schubert 292-263 2,406,772 9/1946 Hunter 292277 X FRED C. MA'ITERN, JR., Primary Examiner. C. F. GREEN, Assistant Examiner. 

